Optical switching device using spectral trigger

ABSTRACT

An apparatus comprising a processor, wherein the processor is configured to split an optical signal into a first optical signal and a second optical signal, wherein the first optical signal comprises a plurality of encoded wavelengths, receive a selection signal, wherein the selection signal selects a plurality of active wavelengths, wherein the active wavelengths are a subset of the encoded wavelengths, compute the routing information for the second optical signal using the active wavelengths, and switch the second optical signal using the routing information.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/591,628 filed Jan. 27, 2012 by Peter Ashwood-Smithand entitled “Spectral Encoding of an Optical Label or Destination” andU.S. Provisional Patent Application No. 61/591,441 filed Jan. 27, 2012by Peter Ashwood-Smith and entitled “Optical Switching Device UsingSpectral Trigger,” both of which are incorporated herein by reference asif reproduced in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Optical networks have become important in today's communication and datanetworks. Data is transferred using optical fibers, which are generallythinner, cheaper, and lighter than copper cables found in networks thatoperate in the electrical domain. Moreover, the capacity of opticalfibers continues to increase at an extraordinary rate. Optical networksenable large amounts of data to be transferred through optical fibers atvery high data rates and over very long distances. Transmission over anoptical network may be implemented using a variety of network systems,such as Wavelength Division Multiplexing (WDM), Synchronous OpticalNetwork (SONET)/Synchronous Digital Hierarchy (SDH), and optical packetnetworks. However, similar to other network technologies, opticalnetworks have their shortcomings.

Despite having a superior medium, optical networks lack the technologyto efficiently route and switch the massive amounts of optical data.Optical networks may comprise electrical, optical-electrical, or pureoptical components. Unfortunately, development of pure opticalcomponents is still in the infancy stages, while electrical componentsand optical-electrical components are generally too slow to process themassive amounts of optical data. Furthermore, many optical networksrequire an optical-to-electrical conversion prior to processing theoptical signal. The optical-to-electrical conversion transforms theoptical signal into an electrical signal. Once in the electrical domain,electrical components, such as switches, routers, and regenerators, maybe used to process the electrical signal. Subsequently, anelectrical-to-optical converter transforms the electrical signal backinto an optical signal. The conversion and electrical processing notonly reduces an optical network's throughput, but also increases thecomplexity of the optical network.

One method to increase routing, switching, and processing speeds inoptical networks is to efficiently process the header informationencoded in the optical signal, such as a destination address or label.Efficiently processing the header information for an optical signalenables components in a network to execute faster routing or switchingdecisions. Current technology enables encoding a label or destinationaddress using a single wavelength of light. However, because atransmitting laser operates within a finite range of wavelengths oflight and at discrete values, the number of different destinationaddresses or labels is severely limited for an optical network. As aresult, other technological alternatives are necessary to efficientlyroute optical signals through an optical network without electricalconversion.

SUMMARY

In one embodiment, an apparatus comprising a processor, wherein theprocessor is configured to split an optical signal into a first opticalsignal and a second optical signal, wherein the first optical signalcomprises a plurality of encoded wavelengths, receive a selectionsignal, wherein the selection signal selects a plurality of activewavelengths, wherein the active wavelengths are a subset of the encodedwavelengths, compute the routing information for the second opticalsignal using the active wavelengths, and switch the second opticalsignal using the routing information.

In another embodiment, the disclosure includes an apparatus comprising afirst single-stage component comprising a first output port and a secondoutput port, a second single-stage component coupled to the first outputport, and a third single-stage component coupled to the second outputport, wherein the first single-stage component is configured to receivean optical signal comprising a plurality of encoded wavelengths, receivea first selection message from a selection logic unit, and switch theoptical signal to one of the output ports using the encoded wavelengthsand the first selection message, wherein the selection logic unit isconfigured to transmit a second selection message to the secondsingle-stage component and to the third single-stage component.

In yet another embodiment, the disclosure includes a method comprisingdecoding a destination address encoded in an optical signal to asequence of bits using spectrum analysis, partition the destinationaddress into a plurality of segments, wherein each segment comprises onedata value for a bit position in the destination address, wherein eachsegment has data values for different bit positions in the destinationaddress, selecting a first segment, routing the optical signal in anoptical network using a first segment, selecting a second segment, androuting the optical signal using a second segment after the opticalsignal has been routed using the first segment.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a schematic diagram of an embodiment of a framework configuredto encode and decode the header information within an optical signal.

FIG. 2 is a schematic diagram of another embodiment of a node configuredto decode and route an optical signal.

FIG. 3 is a schematic diagram of another embodiment of a node configuredto decode the header information encoded in an optical signal.

FIG. 4 is a schematic diagram of another embodiment of a frameworkconfigured to encode and decode the header information within an opticalsignal.

FIG. 5 is a schematic diagram of another embodiment of a node configuredto decode the header information encoded in an optical signal.

FIG. 6 is a schematic diagram of an embodiment of a network componentused for multi-stage switching.

FIG. 7 is a schematic diagram of an embodiment of a multi-stagecomponent comprising a plurality of common network components.

FIG. 8 is a schematic diagram of an embodiment of a general-purposecomputer system.

DETAILED DESCRIPTION

It should be understood at the outset that although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

Disclosed herein is a system and method to encode and decode an opticalheader, such as a destination address or label, within an opticalsignal. Wavelengths of light and polarization of light will bereferenced as wavelengths and polarizations throughout the disclosurefor conciseness purposes. Multiple wavelengths may be selected as asubset of available wavelengths in an optical network to encode theheader information from an incoming electrical data signal. Theselection process for the wavelengths may be based on a function of theheader information, such as the destination address or label. Applyingrelative power levels and utilizing different polarizations may furtherincrease the number of different destination addresses or labels thatcan be encoded beyond the range of tunable wavelengths of a lasertransmitter. The incoming electrical data signal, including the headerinformation, may be inversed multiplexed over the selected wavelengthsand transmitted through the optical network. Another node within theoptical network may receive the optical signal and perform a spectrumanalysis (i.e., FT or equivalent spectral analysis) to produce powerspectrum data. The power spectrum data may then be reversed mapped toobtain the header information initially encoded in the incomingelectrical data signal. The header information may then be used toconfigure the switching behavior of downstream nodes in order to routethe optical signal. The optical signal may be routed using asingle-stage or multi-stage optical device. The multi-stage opticaldevice may be constructed by stacking or cascading common single-stageoptical components. Each single-stage optical component may route theoptical signal based on a portion or subset of the header information bychoosing to only act on a subset of the power spectrum informationdecoded.

FIG. 1 is a schematic diagram of an embodiment of a framework thatencodes and decodes the header information within an optical signal 124.Specifically, FIG. 1 illustrates node 100 encoding an electrical signalinto an optical signal 124 and transmitting the optical signal 124through optical network 122. Node 110 may extract the headinginformation from optical signal 124 to produce routing instructions todownstream nodes 120. Based on the routing instructions, the downstreamnodes 120 may switch or route the optical signal 124 to the desireddestination. The optical network 122 may be implemented using a varietyof optical network systems that may include WDM and optical packetnetworks. The optical network 122 may comprise a plurality of nodes 100,110, 120 interconnected using fiber optic links 108. The nodes 100, 110,120 may be pure optical network devices or optical-electrical networkdevices. The network devices may be terminals, switches, or any othertype of network devices that are able to receive, transmit, route, andprocess optical or electrical data signals. The fiber optic links 108may be any type of connection used to transport optical signals 124,126.

A node 100 may receive an incoming electrical data signal. The node 100may functionally comprise a look up module 102, a lookup wavelengthmodule 104, and a transmitting module 106. To implement the differentmodules 102, 104, and 106, node 100 may comprise a single network deviceor a plurality of interconnected electrical network devices (e.g.,switches and routers), optical network devices, optical-electricalnetwork devices, or any combination thereof. More specifically, node 100may comprise electrical-to-optical converter devices, switchingelements, add/drop nodes, optical transmitters and/or other networkdevices that permit converting an electrical signal to an optical signal124 and subsequently transmitting the optical signal 124.

An incoming electrical data signal may comprise header information, suchas a destination address or label. The header information may comprise asequence of bits. The incoming electrical data signal may be any OpenSystems Interconnection (OSI) layer 2 or layer 3 encoded data signal,such as an Ethernet frame or an Internet Protocol (IP) packet. Theheader information may be encoded as a sequence of bits in a variety ofprotocols, such as multi-protocol label switching (MPLS), AsynchronousTransfer Mode (ATM), Ethernet, Internet Protocol version 4 (IPv4), andInternet Protocol version 6 (IPv6). The header information may be adestination address encoded in an Ethernet frame, MPLS frame, IP packetor other similar types of data signals. The header information may be alabel used in various protocols, such as a label in multi-protocol labelswitching (MPLS), data link connection identifier label (DLCI) in framerelay protocols, or a designated timeslot for time division multiplexing(TDM).

The lookup module 102 may be any device configured to determine thecontents of the header information for the incoming electrical datasignal. The lookup module 102 may comprise a lookup table, routing tableor other similar lookup protocols that may reference the label ordestination address in the incoming electrical data signal to determinerouting information. For example, in a MPLS system, the incoming MPLSlabel may be used as a reference to look up information in the labelforwarding information base (LFIB). In some instances, the lookupprocess may separate the header information from the data portion of theincoming electrical data signal. The header information may comprise asequence of bits that may dictate the transmission path to a networkdestination. In particular, the header information may provide therouting or the next hop instructions for subsequent downstream nodes 120in the optical network 122.

Once the lookup module 102 obtains the header information, the look upwavelength module 104 selects a unique subset of wavelengths “W” from alarger set of available wavelengths “S.” The available wavelengths “S”may include all the usable wavelengths for the optical network 122 orthe transmitting module 106. Wavelengths in subset “W” may be used toencode the header information bit-by-bit. Furthermore, subset “W” mayinclude wavelengths that have the same wavelength values but havedifferent polarizations. Dependent on the optical network's ability forpolarization control, various polarizations for a given wavelength mayconstitute different wavelengths for the optical encoding process.

The selection of subset “W” from available wavelengths “S” may be basedon a function of the header information “E” (e.g., W=Function (E)). Oneembodiment of the selection of wavelength Function (E) may be 2*N+V(e.g., Function (E)=2*N+V). The N variable indicates the bit positionfor the header information “E,” while the V variable indicates the bitvalue for the bit position referenced by N. Applying the 2*N+V function,the encoding process may produce a two-to-one relationship between thesubset of wavelengths “W” and the number of bits in the headerinformation “E.” For example, the header information may be a 10 bitdestination address with bit positions d₉-d₀ that may be encoded using20 wavelengths λ₁₉-λ₀. Bit d₀ may represent bit position zero, while bitd₁ may represent bit position one. Bits d₉-d₂ may follow the same bitposition allocation. Two wavelengths may be assigned to each bitposition to encoded different data values at the bit position. For bitd₀, wavelengths λ₀ and λ₁ may be used to encode the “0” and “1” datavalues, respectively. Applying the two-to-one relationship, 2^(M/2)destinations may be encoded, where “M” is the number of selectedwavelengths. The number of available wavelengths “S” may be increased bycategorizing wavelengths with the same wavelength value but differentpolarizations as separate wavelengths. Node 100 may be configured toimplement other methods or algorithms to assign wavelengths to subset“W.” Persons of ordinary skill in the art are aware that there are anabundant number of permutations in selecting a subset “W” from availablewavelengths “S” as a function of the header information “E.”

Wavelengths in subset “W” with different polarizations may be treated asdifferent encoding wavelengths even though the wavelengths have the samewavelength values. For example, wavelengths λ₀ and λ₁ may have the samewavelength value, but wavelength λ₀ may be polarized in the x-direction,while wavelength λ₁ may be polarized in the y-direction. As such,wavelengths with the same wavelength values may be used to encode thesame bit position d₀. Utilization of different polarizations may beimplemented using polarization control for the optical network, such aspolarization-dependent optical switches.

After the lookup wavelength module 104 selects wavelengths for subset“W,” the wavelength information and electrical signal may be sent to thetransmitting module 106. The transmitting module 106 may inversemultiplex the incoming electrical data signal over the wavelengths insubset “W.” The summation of the wavelengths and polarizations in subset“W” may represent the non-header or data portion of the incomingelectrical data signal. Inverse multiplexing the incoming electricaldata signal may require segmenting or dividing the incoming electricaldata signal. The incoming electrical data signal may be segmented intomultiple lower data rate segments. Inverse multiplexing the electricaldata signal may be implemented using a variety schemes such as MultiLink Point-to-Point Protocol (PPP), Ethernet's Link Aggregation, orInverse Multiplexing for ATM (IMA). The segmented portions of theincoming electrical data signal may then be mapped to the wavelengthsand polarizations in subset “W.”

Additionally, subset “W” may be used to encode the header information.The header information may be encoded bit-by-bit, perhaps including thepreamble. Source address data may not need to be encoded using subset“W.” Using a laser transmitter, power may be applied to the wavelengthsin subset “W” based on the data values in the header information. Forexample, the wavelengths λ₁₉-λ₀ may be selected to encode a 10 bitdestination address “E” d₉-d₀ that equals a data value of “1000110001. ”Applying the selection function 2*N+V as the Function (E) embodiment,the transmitting module 106 may apply power to wavelengths λ₁, λ₂, λ₄,λ₆, λ₉, λ₁₁, λ₁₂, λ₁₄, λ₁₆, and λ₁₉. Other wavelengths in subset “W” λ₀,λ₃, λ₅, λ₇, λ₈, λ₁₀, λ₁₃, λ₁₅, λ₁₇, and λ₁₈ may have relatively muchlower or no power applied. Other embodiments to map and encode theheader information may be implemented as long as more power is appliedto wavelengths in subset “W” than the entire wavelength set. To ensuresignal quality, signal padding may be added to the optical signal 124prior to the transmission. Afterwards, the optical signal 124 may betransmitted through an optical fiber link 108 in the optical network122.

Node 110 may receive the optical signal 124 traveling through theoptical fiber link 108. Node 110 may functionally comprise an opticalsplitter 112, FT unit 114, computational logic 116, and a delay module118. Similar to the node 100, node 110 may comprise a single networkdevice or a plurality of optical network devices, optical-electricalnetwork devices, or any combination thereof to implement node's 110functions. Node 110 may be configured to provide polarization controland to process a plurality of optical signals 124. As shown in FIG. 1,node 110 may be configured to extract the header information from theoptical signal 124 without converting the entire optical signal 124 backinto an electrical signal. Identification of the label or destinationaddress may not require synchronization of or identification of bitswithin the optical packet. Moreover, bit-by-bit reconstruction of theentire optical signal 124 may not be necessary to determine thedestination or label, and therefore the subsequent switching action.

Once, node 110 receives optical signal 124, a portion of the opticalsignal 124 is separated using the optical splitter 112 or a similardevice. The optical splitter 112 may be a passive optical component thatmay comprise an input port with a plurality of output ports. The opticalsplitter 112 may be configured to separate a plurality of opticalsegments from the optical signal 124. In FIG. 1, the optical splitter112 may be configured to have two outputs ports. One output port may becoupled to the FT unit 114 while another output port may be coupled tothe delay module 118. The optical splitter 112 may separate an opticalsegment 125 from the optical signal 124 used to extract the headerinformation and may provide next hop information or routinginstructions. The separated optical segment 125 may comprise arelatively small percentage of the optical signal 124 (e.g., 1-10%). Theremaining optical signal 126 comprises a majority of the optical signal124 (e.g., 90-99%) and is outputted to the delay module 118.

The FT unit 114 may perform a spectrum analysis (i.e., FT) on theseparated optical segment. FT unit 114 may comprise a plurality ofoptical, optical-electrical, electrical components, or any combinationthereof. The spectrum analysis produces the power spectrum for theseparated optical segment. The power spectrum may contain energy peaksthat correspond to the wavelengths in subset “W.” The energy peaks inthe power spectrum data may correspond to the wavelengths that receivedmore power when encoding the optical signal. Existence of energy peaksfor each wavelength may depend on the data values in the header. Forexample, a 10 bit destination address “E” d₉-d₀₋may equal a data valueof “1000110001.” In this instance, the power spectrum data may haveenergy peaks at wavelengths λ₁, λ₂, λ₄, λ₆, λ₉, λ₁₁, λ₁₂, λ₁₄, λ₁₆, andλ₁₉. The FT unit 114 may separate different polarizations prior toperforming the spectrum analysis, and thus may produce different powerspectrum data for the different polarizations. The FT unit 114 may becoupled to the computational logic 116 and may output the power spectrumdata to the computational logic 116. The FT unit 114 may perform thespectrum analysis in the electrical domain or in the optical domain.

The computational logic 116 may be an optical-electrical and/orelectrical device configured to process analog or digital signals. Morespecifically, the computational logic 116 may comprise a plurality ofinputs and outputs, power detectors, processors, and any other opticalor electrical components capable of processing the power spectrum data.The inputs for the computational logic 116 may be coupled to the FT unit114 and may be electrical inputs (i.e., inputs configured to receiveelectrical signals). The computational logic 116 may decode the headerinformation by reverse mapping the power spectrum data from the FT unit114. The reverse mapping process may determine the data values of theheader information by applying the inverse of Function (E) to the powerspectrum data (i.e., Function⁻¹(power spectrum data)=E). The inversefunction of the power spectrum data may map the energy peaks to the datavalues and bit positions in the header information. By reverse mappingthe wavelengths, the header information may be extracted withoutbit-by-bit reconstruction of the entire optical signal. Moreover, thedecoding or reverse mapping process may not require optical andelectrical synchronization.

The computational logic 116 may use the decoded header information toprovide instructions to downstream nodes 120 to route or switch theremaining optical signal 126 to the next hop or destination node. Thecomputational logic 116 may implement a full lookup, where the entiredecoded header information (e.g., destination address or label) isinputted into a single downstream node 120. Partial lookups arediscussed in further detail below. Additionally, the header informationmay program or configure a plurality of downstream nodes 120 necessaryto route the remaining optical signal. The downstream nodes 120 may bemultiple hops from node 110. The reverse mapping process (i.e., decodingprocess) and lookup process may be performed in the electrical domain orpartially in the electrical domain. Other reverse mapping and look upembodiments may be used to extract the header information encoded inoptical signal 124.

The computational logic 116 may output the decoded header informationthat may comprise a destination address, label information, or any othertypes of routing instructions to downstream nodes 120. The downstreamnodes 120 may be optical or optical-electrical devices configured toreceive electrical routing instructions, destination addresses, orlabels. The downstream nodes 120 may be a single device or may comprisea plurality of optical, optical-electrical, or electrical devices thatmay be polarization-dependent. The downstream nodes 120 may comprise aplurality of electrical inputs coupled to the computational logic 116.The downstream nodes 120 may comprise N inputs coupled to thecomputational logic 116 and M output ports to route the remainingoptical signal 126. The downstream nodes 120 outputs the optical signalto an output port depending on the header information received fromcomputational logic 116. Nodes 120 may be part of node 110 (e.g. opticalswitches within a single device) or downstream nodes in separatedevices.

In addition to the electrical inputs coupled to the computational logic116, the downstream nodes 120 may have optical inputs coupled to otherdownstream nodes or to the delay module 118. In FIG. 1, downstream nodeA 120 may receive the remaining optical signal 126 from the delay module118. Downstream node A 120 may switch or route the remaining opticalsignal 126 based on the heading information received from thecomputational logic 116. Downstream node A 120 may output the remainingoptical signal 126 to downstream node B 120 or to some other downstreamnode 120 not shown in FIG. 1. The downstream node A 120 may switch orroute the remaining optical signal 126 without performing anoptical-to-electrical conversion or decoding the entire remainingoptical signal 126 bit-by-bit. Moreover routing of the remaining opticalsignal 126 may be routed using multiple stages. Each stage may route theremaining optical signal 126 using a unique section of the headerinformation. Multi-stage switching will be discussed more in detaillater.

While the header information is decoded using the separated opticalsegment, the remaining optical signal 126 may be directed to the delaymodule 118. The delay module 118 may be an optical buffer that providesa fixed delay equivalent to the amount of time necessary to decode theheader information and to configure the downstream nodes 120. The fixeddelay may also depend on the processing speeds of the various optical,optical-electrical, and electrical components used to decode the headerinformation from the separated optical segment. The delay module 118 maybe implemented using a variety of methods, such as recirculating delaylines or cascaded delay lines.

FIG. 2 is a schematic diagram of another embodiment of a node 214 thatis configured to decode and route an optical signal. Node 214 may besimilar to node 110 except node 214 may further comprise a switchingmodule 208 to route the optical signal 200. Node 214 may comprise anoptical splitter 202, FT logic unit 204, computational logic 206, and adelay module 210, which are the same as components 112, 114, 116, and118 as discussed above. The switching module 208 may comprise aplurality of electrical inputs coupled to the computational logic 206and a plurality of optical inputs coupled to the delay module 210. Therouting or switching module 208 may be an optical or optical-electricalcomponent that performs the same function as the downstream nodes 120 inFIG. 1. FIG. 2 illustrates the optical signal 200 may have power orenergy peaks for wavelengths 1, 4, and 6. Additionally, node 214 mayoutput an optical signal 200 comprising the same wavelengths as theincoming optical signal 200. Other embodiments of node 214 may alter thewavelengths and polarizations outputted by node 214. For example, thenode 214 may need to encode a new label for the optical signal 200, andthus outputs an optical signal 200 comprising wavelengths 2, 5, and 7.

FIG. 3 is a schematic diagram of another embodiment of a node 314 todecode and route an optical signal. Node 314 is the same as node 214,but uses resonator rings 302 to implement the FT logic unit 204 andcomprises a plurality of power detectors 304, a plurality of 1:2switching devices 310 and computational logic devices 306 that mayperform a logical function equivalent to an AND gate with an inverterattached to one of the inputs. The optical splitter 300, and the delaymodule 308 are the same as the optical splitter 112 and 202. In FIG. 3,the header information may be a 10 bit destination address d₉-d₀ using20 available wavelengths λ₁₉-λ₀. When a bit position d₀ has a data valueof zero, bit position d₀ may be encoded using wavelengths λ₀. However,when the same bit position d₀ has a data value of one, a secondwavelength λ₁ may be used to encode the bit position d₀. The sametwo-to-one mapping relationship may apply for the remaining bitpositions d₉-d₁ and remaining wavelengths λ₁₉-λ₂.

Similar to optical splitter 112 and 202, optical splitter 300 mayseparate a small fraction of an optical signal (e.g., 1-10%) to decodethe header information. Subsequently, the segmented optical signal isforwarded to the resonator rings 302. The resonator rings 302 may betuned to resonate at a designated wavelength. In FIG. 3, the resonatorring 302 for λ₀ may be tuned to resonate only at the wavelength valuefor λ₀. Other wavelengths may be filtered out and the power spectrumdata may not be forwarded to the power evaluator device 304. Theresonator rings 302 may also be configured to extract the power spectrumdata for the designated wavelength. The power spectrum data may containenergy peaks that correlate with the encoded destination address. Forexample, if bit position d₀ contained a value of zero, then theresonator ring 302 for λ₀ would produce an energy peak for the λ₀'swavelength value, while the resonator ring 302 for λ₁ would not producean energy peak. The resonator rings 302 may extract the power spectrumin an analog fashion. Other embodiments may utilize different methods ordevices to extract the power spectrum data. The extracted power spectrumdata may be analog or digital signals.

Each resonator ring 302 may be coupled to a power evaluator device 304to determine whether an energy peak exists for a designated wavelength.As stated above, each resonator ring 302 may be tuned for a designatedwavelength. The resonator ring 302 inputs the power spectrum data into apower evaluator device 304. The power evaluator device 304 may analyzethe power levels and determine whether an energy peak exists in thepower spectrum data for the designated wavelength. Based on whether anenergy peak exists, the power evaluator device 304 may output a logicsignal to the computational logic device 306. The logic signal may be ananalog or digital signal and may comprise a single bit or a sequence ofbits. Using FIG. 3 as an example, if no energy peak was detected forwavelength λ₀, the power evaluator device 304 may output a data value ofzero. Conversely, if an energy peak was detected for wavelength λ₀, thepower evaluator device 304 may output a data value of one. The powerevaluator device may be a power detector or any other similar devicecapable of measuring power from an optical signal.

The power evaluator device 304 may be coupled to a computational logicdevice 306 to perform the reverse mapping and look up functions. Thecomputational logic device 306 may use the input received to generate adata value on the destination address data line 312. As shown in FIG. 3,the computational logic device 306 may perform a logical functionequivalent to an AND gate with an inverter attached to one of theinputs. The inverter may be attached for inputs that correspond towavelengths that represent zero data values for the header information.For example, a computational logic device 306 may be configured toprocess the power evaluator data for wavelength λ₀ and wavelength λ₁.Wavelength λ₀ may represent a zero data value for bit position d₀ whilewavelength λ₁ may represent a one data value for bit position d₀. Assuch, an inverter may be attached to the input originating from thepower evaluator device 304 that corresponds to wavelength λ₀. Thecomputational logic device 306 receives the data values from the powerevaluator devices 304 and generates a data value for the destinationaddress data line d₀ 312. The data value may a single bit or a sequenceof bits. The data value may be an analog or digital signal. Thedestination address data line 312 may then input the data value into theinput selector ports for switching devices 310.

In FIG. 3, the switching device 310 may be a 1:2 switching device. A 1:2switching device routes an optical signal to two possible output portsbased on one selection input. The switching device 310 routes theoptical signal to output port “0” when the input selector port has adata value of zero. Alternatively, the switching device 310 may switchthe optical signal to output port “1” when the input selector port has adata value of one. Although FIG. 3 illustrates utilizing a plurality of1:2 (i.e., N=1; M=2) switching devices 310, other embodiments mayinclude switching devices 310 with different N and M values (e.g., a 1:Mswitching device). The routing of the optical signal may be implementedusing a plurality of switching devices 310 coupled to each other asshown in FIG. 3. Another embodiment may route the optical signal using asingle switching device 310.

FIG. 4 is a schematic diagram of another embodiment of a framework thatencodes and decodes the header information within an optical signal.Lookup module 402, optical fibers 408, optical splitter 412, FT unit414, delay module 418, and downstream nodes 420 are the same as thecomponents 102, 108, 112, 114, 118, and 120 shown in FIG. 1. The powerlevel lookup module 404, power level transmitting module 406, and powerlevel computational logic 416 differ from FIG. 1.

The power level look up module 404 in node 400 selects a unique subsetof wavelengths “W” based on wavelength values, polarization, andrelative power levels from a larger set of available wavelengths “S.”Using relative power levels, a one-to-one relationship may exist betweenthe number of selected wavelengths for subset “W” and the number of bitsin the header information. The function or selection algorithm mayselect wavelengths based on the different wavelength values and relativepower levels. For example, the header information may be a 10 bitdestination address d₉-d₀ that may be encoded using 10 wavelengthsλ_(9—)λ₀ at a relatively high power level and a relatively low powerlevel. Using the one-to-one relationship, 2^(M) destinations using tworelative power levels may be encoded, where “M” is the number ofselected wavelengths. Other embodiments may employ selection methods orfunctions that use more than two relative power levels to encode theheader information.

The power level transmitting node 406 may subsequently inverse multiplexthe entire incoming electrical data signal, including the headerinformation over the wavelengths in subset “W” to form an opticalsignal. As stated above, the encoding process may use wavelengths withrelative power levels. Relative power levels may be applied to thewavelengths in subset “W” depending on the data values in the containedheader information. For example, a destination address d₉-d₀ that equals“1000110001,” wavelengths λ_(9—)X₀ may be assigned to subset “W” whenutilizing two relative power levels. A relatively low power level mayindicate a data value of zero and a relatively higher power level mayindicate a data value of one. Hence, for bit position d₀, wavelength λ₀may have a relatively high power level. The summation of the wavelengthsin subset “W” may also represent the data encoded in the incomingelectrical data signal. Other encoding methods may be used as long asdistinguishable relative power levels are used for all wavelengths insubset “W.” The optical signal may be padded to ensure energydistribution.

After node 410 receives and splits the optical signal 424 into aseparated optical segment 425 and remaining optical segment 426, the FTunit 414 may perform a spectrum analysis to produce a power spectrumusing the separated optical segment 425. The power spectrum may includepeaks that correspond with members of the subset “W.” The relativeheights of the peaks provide the relative power levels selected for thedifferent wavelengths. The relative heights for each wavelength maydepend on the data values for the header information. Similar to the FTunit 114 in FIG. 1, the FT unit 414 may separate out differentpolarizations to produce different power spectrum data for wavelengthsthat have the same wavelength values. Moreover, the FT unit 414 mayperform the spectrum analysis in the electrical domain or in the opticaldomain.

The power level computational logic 416 may then reverse map the powerspectrum data received from the FT unit 414. The wavelengths of subset“W” may have a one-to-one mapping function for the header information.By reverse mapping based on the wavelengths, relative power levels, andpolarization, the header information may be recreated. The relativepower levels may represent the data values for each bit position in theheader information. Every bit of the header information, perhapsincluding the preamble, may be identified using the reverse mappingprocess without understanding the contents of the optical signal.

FIG. 5 is a schematic diagram of another embodiment of a node 514configured to decode the header information encoded in an opticalsignal. Node 514 is similar to node 314 except that the headerinformation may be a 10 bit destination address d₉-d₀ encoded with 10wavelengths λ_(9—)λ₀. Optical splitter 500, resonator rings 502,computational logic devices 506, delay module 508, switching module 510,and destination address data line 512 are similar to components 300,302, 306, 308, 310, and 312 shown in FIG. 3. When a bit position d₀ hasa data value of zero, the bit position may be encoded using one of thewavelengths λ₀ with a relatively low power level. When the same bitposition d₀ has a data value of one, wavelength λ₀ may be encoded withrelatively higher power level.

In contrast to FIG. 3, each resonator ring 502 may be coupled to twopower evaluator devices 504 to decode the relative power level peaks.The resonator ring outputs the power spectrum data to both powerevaluator devices 504. One power evaluator device “Power 0” 504 mayevaluate the power spectrum data to determine whether the energy peakequates to a relatively lower power level. A second evaluator device“Power 1” 504 may determine whether the energy peak equates to arelatively higher power level. Thus, both power evaluators “Power 0,”“Power 1” 504 may output the data values that are dependent on relativepower levels for a given wavelength. Using FIG. 5 as an example, if arelatively low power level was applied to wavelength λ₀ during theencoding process, the power evaluator device 504 “Power 0” may output asignal with data value of one. Conversely, the power evaluator device504 “Power 1” would output a signal with data value of zero. The datavalues may be analog or digital signals.

FIG. 6 is a schematic diagram of an embodiment of a network component600 used for multi-stage switching. The network component 600 comprisesan optical splitter component 602, resonator ring components 604, powerevaluator components 606, an optical buffer component 612, and aswitching component 618 that are the same as components 300, 302, 304,308, and 310 shown in FIG. 3. The network component 600 furthercomprises different computational logic components 608, wavelengthselection inputs 610, an amplifier 614, and an amplifier control input616.

The optical buffer 612 delays and forwards an optical signal to anoptical amplifier component 614. The optical amplifier component 614 maybe used to regenerate or amplify the optical signal. The opticalamplifier component 614 may be an optical device or anoptical-electrical device. Examples of optical amplifier components 614may be Erbium-doped fiber amplifier (EDFA), other semiconductor opticalamplifier, or a regenerator that requires conversion to the electricaldomain. An amplifier control input 616 may be provided by an external orinternal source.

Similar to computational logic devices 306 shown in FIG. 3, thecomputational logic component 608 receives the data values from thepower evaluator devices 606. However, the computational logic component608 may have three input ports and one output port. Two different powerevaluator components 606 may provide the input signal for two of theinput ports. The third input port may be for the wavelength selectioninput 610. The computational logic component 608 may perform a logicalfunction equivalent to an AND gate with an inverter attached to one ofthe inputs. The wavelength selection input 610 may be supplied by anexternal or internal source.

An external source may provide data for the wavelength selection inputs610 to control the wavelengths used in the switching operation. FIG. 6illustrates data for the wavelength selection inputs S₉-S₀ 610 may beprovided through parallel communication. Another embodiment may have thenetwork component 600 to process the wavelength selection inputs S₉-S₀serially. Wavelength selection input 610 selects a subset of thewavelengths in the separated optical segment to route the remainingoptical signal. For example, when wavelength selection input 610 S₉ hasa logical value of 1, and S_(8—)S₀ have a data value of zero,wavelengths λ₁₈ and λ₁₉ or destination address d₉ may affect theswitching component 618. Other destination address bits d₈-d₀ may nothave been selected, and thus may not affect the switching component 618.In this instance, wavelengths λ₁₈ and λ₁₉ or destination address d₉ mayconfigure the switching component to route the remaining optical signalto a particular output.

Another embodiment may have the power evaluator component 606 andcomputational logic devices 608 configured to detect relative powerlevels or relative heights in the energy peaks as shown in FIG. 5. Theinverter may be attached for inputs that correspond to wavelengths thatrepresent zero data values for the header information. The embodimentmay have the inverter attached to the “Power 0” power evaluatorcomponent 606 when the encoding process involves using relative powerlevels. Dependent on the input values, the computational logic component608 processes the inputted values and outputs a resulting value to theswitching component 618. The resulting value may be a single bit or asequence of bits.

FIG. 7 is a schematic diagram of an embodiment of a multi-stagecomponent 700 comprising a plurality of common network components 701.The multi-stage component 700 may comprise common network components 701coupled together to route an optical signal based on the encoded headerinformation. FIG. 7 illustrates network component A 701 coupled tonetwork components B and C 701. In other embodiments, network componentA 701 may be coupled to more than two common network components 701.Moreover, network components' B and C 701 output ports may be coupled toadditional common network components 701 to form additional stages ofthe optical routing process. Each common network component 701 maycomprise an optical splitter component 702, resonator ring components704, power evaluator components 706, computational logic components 708,wavelength selection inputs 710, a delay module 712, an amplifiercomponent 714, an amplifier control input 716, and a switching component718 that are the same as to the components 602, 604, 606, 608, 610, 612,614, 616, and 618 as discussed above.

In FIG. 7, common network component 701 A may be configured to route anincoming signal based on the d₀ bit in the header information. The S₀wavelength selection input 710 may be assigned a data value of one whileS₉-S₁ may have a data value of zero. The value of d₀ determines whetherthe optical signal is routed to network component B 701 or networkcomponent C 701. For example, if d₀ had a data value of one, the opticalsignal may be routed to network component B 701. However, if d₀ had adata value of zero, the optical signal may be routed to networkcomponent C 701. Network component B and C 701 may have a data value ofone for S₁ wavelength selection input 710. Other wavelength selectioninputs S₉-S₂, S₀ 710 may have a data value of zero. As a result, networkcomponent B and C 701 may route any optical signal based on the value ofd₁. Additional common network components 701 may be coupled to formstages necessary to evaluate the remaining destination bits d₉-d₂. Themulti-stage component 700 may be constructed such that the additionalcommon network components 701 for each stage may be coupled in the samemanner as how network components B and C 701 are coupled to networkcomponent A 701. The common network components 701 forming themulti-stage component 700 may be coupled such that common networkcomponents 701 may be situated in one location of the optical network orin different locations of the optical network.

The network components and devices described above may be implemented onany general-purpose network component, such as a computer or networkcomponent with sufficient processing power, memory resources, andnetwork throughput capability to handle the necessary workload placedupon it. FIG. 8 illustrates a typical, general-purpose network component800 that may correspond to or may be part of a network component, suchas a server, a switch, a router, or any other network nodes. The networkcomponent 800 includes a processor 802 (which may be referred to as acentral processor unit or CPU) that is in communication with memorydevices including secondary storage 804, read only memory (ROM) 806,random access memory (RAM) 808, input/output (I/O) devices 810, andnetwork connectivity devices 812. The general-purpose network component800 may also comprise, at the processor 802 and or any of the othercomponents of the general-purpose network component 800.

The processor 802 may be implemented as one or more CPU chips, or may bepart of one or more application specific integrated circuits (ASICs)and/or digital signal processors (DSPs). The processor 802 may comprisea central processor unit or CPU. The processor may be implemented as oneor more CPU chips. The secondary storage 804 is typically comprised ofone or more disk drives or tape drives and is used for non-volatilestorage of data and as an over-flow data storage device if RAM 808 isnot large enough to hold all working data. Secondary storage 804 may beused to store programs that are loaded into RAM 808 when such programsare selected for execution. The ROM 806 is used to store instructionsand perhaps data that are read during program execution. ROM 806 is anon-volatile memory device that typically has a small memory capacityrelative to the larger memory capacity of secondary storage 804. The RAM808 is used to store volatile data and perhaps to store instructions.Access to both ROM 806 and RAM 808 is typically faster than to secondarystorage 804.

The secondary storage 804 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if RAM 808 is not large enough tohold all working data. Secondary storage 804 may be used to storeprograms that are loaded into RAM 808 when such programs are selectedfor execution. The ROM 806 is used to store instructions and perhapsdata that are read during program execution. ROM 806 is a non-volatilememory device that typically has a small memory capacity relative to thelarger memory capacity of secondary storage 804. The RAM 808 is used tostore volatile data and perhaps to store instructions. Access to bothROM 806 and RAM 808 is typically faster than to secondary storage 804.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R₁, and an upper limit,R_(u), is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R₁+k*(R_(u)−R₁), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 7 percent, . . . , 70percent, 71 percent, 72 percent, . . . , 97 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed. The use of the term about means ±10% of thesubsequent number, unless otherwise stated. Use of the term “optionally”with respect to any element of a claim means that the element isrequired, or alternatively, the element is not required, bothalternatives being within the scope of the claim. Use of broader termssuch as comprises, includes, and having should be understood to providesupport for narrower terms such as consisting of, consisting essentiallyof, and comprised substantially of. Accordingly, the scope of protectionis not limited by the description set out above but is defined by theclaims that follow, that scope including all equivalents of the subjectmatter of the claims. Each and every claim is incorporated as furtherdisclosure into the specification and the claims are embodiment(s) ofthe present disclosure. The discussion of a reference in the disclosureis not an admission that it is prior art, especially any reference thathas a publication date after the priority date of this application. Thedisclosure of all patents, patent applications, and publications citedin the disclosure are hereby incorporated by reference, to the extentthat they provide exemplary, procedural, or other details supplementaryto the disclosure.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, optical or otherwise. Other examples ofchanges, substitutions, and alterations are ascertainable by one skilledin the art and could be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. An apparatus comprising: an integrated circuit; aprocessor on the integrated circuit, wherein the processor is configuredto: split an optical signal into a first optical signal and a secondoptical signal, wherein the first optical signal comprises a pluralityof encoded wavelengths; receive a selection signal, wherein theselection signal selects a plurality of active wavelengths, wherein theactive wavelengths are a subset of the encoded wavelengths; compute therouting information for the second optical signal using the activewavelengths; and switch the second optical signal using the routinginformation to a downstream component, wherein the optical signalincludes sequential packets.
 2. The apparatus of claim 1, wherein theprocessor is further configured to perform a spectrum analysis on thefirst optical signal to obtain the power spectrum data for the encodedwavelengths and compute the routing information for the second opticalsignal using the power spectrum data for the active wavelengths.
 3. Theapparatus of claim 2, wherein the power spectrum data comprises aplurality of energy peaks, wherein some of the energy peaks representthe active wavelengths, and wherein instructions further cause theprocessor to compute the routing information using the energy peaks thatrepresent the active wavelengths.
 4. The apparatus of claim 3, whereinthe energy peaks comprise a plurality of relative heights, and whereinthe instructions further cause the processor to compute the routinginformation using the relative heights for the active wavelengths. 5.The apparatus of claim 1, wherein the processor is further configured toamplify the second optical signal prior to switching the second opticalsignal.
 6. The apparatus of claim 1, wherein the first optical signalcomprises a destination address header, and wherein the activewavelengths encode a portion of the destination address header.
 7. Theapparatus of claim 6, wherein the processor is further configured tocompute the routing information using the portion of the destinationaddress header.
 8. The apparatus of claim 1, wherein the apparatuscomprises a plurality of output ports, and wherein instructions furthercause the processor to switch the second optical signal to one of theoutput ports using the routing information.
 9. The apparatus of claim 1,wherein the selection signal selects a first encoded wavelength and asecond encoded wavelength as the active wavelengths.
 10. An apparatuscomprising: a first single-stage component comprising a first outputport and a second output port; a second single-stage component coupledto the first output port; and a third single-stage component coupled tothe second output port, wherein the first single-stage component isconfigured to: receive an optical signal comprising a plurality ofencoded wavelengths; receive a first selection message from a selectionlogic unit; and switch the optical signal to one of the output portsusing the encoded wavelengths and the first selection message, whereinconsecutive packets within the optical signal may be switched to a sameone of the output ports, and wherein the selection logic unit isconfigured to transmit a second selection message to the secondsingle-stage component and to the third single-stage component, andwherein the first selection message selects a subset of the encodedwavelengths, and wherein the subset of the encoded wavelengths switchesthe optical signal.
 11. The apparatus of claim 10, wherein the selectionlogic unit is external to the apparatus.
 12. The apparatus of claim 10,wherein the first selection message and the second selection message area sequence of bits, and wherein data values for the first select messageand the second selection message are different.
 13. The apparatus ofclaim 10, wherein the first bit position of the first selection messagehas a one data value, and wherein the second bit position of the firstselection message has a zero data value.
 14. The apparatus of claim 10,wherein the first bit position of the second selection message has azero data value, and wherein the second bit position of the secondselection message has a one data value.
 15. The apparatus of claim 10,wherein the second single-stage component is configured to receive arouted optical signal from the first single-stage component and switchthe optical signal using the second selection message.
 16. The apparatusof claim 15, wherein the third single-stage component is configured toreceive a routed optical signal from the first single-stage componentand switch the optical signal using the second selection message.
 17. Anapparatus comprising: a first single-stage component comprising a firstoutput port and a second output port; a second single-stage componentcoupled to the first output port; and a third single-stage componentcoupled to the second output port, wherein the first single-stagecomponent is configured to: receive an optical signal comprising aplurality of encoded wavelengths; receive a first selection message froma selection logic unit; and switch the optical signal to one of theoutput ports using the encoded wavelengths and the first selectionmessage, wherein consecutive packets within the optical signal may beswitched to a same one of the output ports, and wherein the selectionlogic unit is configured to transmit a second selection message to thesecond single-stage component and to the third single-stage component,and wherein the optical signal comprises a destination address header,wherein the first selection message selects a portion of the destinationaddress header, and wherein the portion determines the output port toswitch the optical signal.
 18. A method comprising: decoding adestination address encoded in an optical signal to a sequence of bitsusing spectrum analysis; partition the destination address into aplurality of segments, wherein each segment comprises one data value fora bit position in the destination address, wherein each segment has datavalues for different bit positions in the destination address; selectinga first segment; routing the optical signal in an optical network usingthe first segment; selecting a second segment; and routing the opticalsignal using the second segment after the optical signal has been routedusing the first segment.
 19. The method of claim 18, wherein the firstsegment comprises a data value for the first bit position in thedestination address, and wherein the second segment comprises a datavalue for the second position in the destination address.